View Full Version : Cadmium Yellow Not Mixable With Copper Based Pigments?

03-11-2014, 05:18 AM
I was reading on the DickBlick site on Cadmium Yellow and it states that "Cadmium Yellow is brilliant, dense, and opaque, with good tinting strength and very high hiding power. It is the artistís principal bright yellow and is available in light, medium, and dark shades. The deeper shades appear deep orange and have the greatest tinting strength. It is slow-drying in oil form and is used in both oil and watercolor form. It cannot be mixed with copper-based pigments. A clean Cadmium Orange is created when Cadmium Yellow is mixed with Cadmium Red. Hues vary by brand. Cadmium pigments have been partially replaced by azo pigments, which are similar in lightfastness to the cadmium colors, cheaper, and non-toxic." According to Wikipedia, the copper-based pigments are Viridian, Phthalo blue & green, and some others. I've never heard of this being a problem, however I would welcome any insight or knowledge to clearing things up for me.

03-11-2014, 04:20 PM
Copper-based pigments which can (only theoretically) react with cadmiums are Verdigris, Copper resinate, Malachite, Azurite and Veronese (Emerald) green. All of these pigments are not in use in oil paint today. Phthalocyanine Green and Blue can't react with Cadmiums, nor with free sulfur, their molecular structure is sulfur-resistant. Phtalocyanine molecules are armor-solid, permanent and inert.